editor/AsyncSpellCheckTestHelper.jsm
author Wes Kocher <wkocher@mozilla.com>
Thu, 09 Jul 2015 17:43:08 -0700
changeset 252149 fb0c6275d5c2b06d8467c9aa69ff2e50af16ecef
parent 134173 eac7a8c8d5d42d0ca047102422e13a9bb4fec50e
child 331338 25c0a38d2d7ed50ed3c1d419f70c01595c481ae7
permissions -rw-r--r--
Backed out 5 changesets (bug 1180921) for build failures in BasePrincipal.cpp Backed out changeset d8c1a2e11a9a (bug 1180921) Backed out changeset f4dd8c53df5f (bug 1180921) Backed out changeset b272a0ebf5d8 (bug 1180921) Backed out changeset 8e86b6a7d201 (bug 1180921) Backed out changeset bbdebd7b8881 (bug 1180921)

/* This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

this.EXPORTED_SYMBOLS = [
  "onSpellCheck",
];

const SPELL_CHECK_ENDED_TOPIC = "inlineSpellChecker-spellCheck-ended";
const SPELL_CHECK_STARTED_TOPIC = "inlineSpellChecker-spellCheck-started";

const { classes: Cc, interfaces: Ci, utils: Cu } = Components;

/**
 * Waits until spell checking has stopped on the given element.
 *
 * When a spell check is pending, this waits indefinitely until the spell check
 * ends.  When a spell check is not pending, it waits a small number of turns of
 * the event loop: if a spell check begins, it resumes waiting indefinitely for
 * the end, and otherwise it stops waiting and calls the callback.
 *
 * This this can therefore trap spell checks that have not started at the time
 * of calling, spell checks that have already started, multiple consecutive
 * spell checks, and the absence of spell checks altogether.
 *
 * @param editableElement  The element being spell checked.
 * @param callback         Called when spell check has completed or enough turns
 *                         of the event loop have passed to determine it has not
 *                         started.
 */
function onSpellCheck(editableElement, callback) {
  let editor = editableElement.editor;
  if (!editor) {
    let win = editableElement.ownerDocument.defaultView;
    editor = win.QueryInterface(Ci.nsIInterfaceRequestor).
                 getInterface(Ci.nsIWebNavigation).
                 QueryInterface(Ci.nsIInterfaceRequestor).
                 getInterface(Ci.nsIEditingSession).
                 getEditorForWindow(win);
  }
  if (!editor)
    throw new Error("Unable to find editor for element " + editableElement);

  try {
    // False is important here.  Pass false so that the inline spell checker
    // isn't created if it doesn't already exist.
    var isc = editor.getInlineSpellChecker(false);
  }
  catch (err) {
    // getInlineSpellChecker throws if spell checking is not enabled instead of
    // just returning null, which seems kind of lame.  (Spell checking is not
    // enabled on Android.)  The point here is only to determine whether spell
    // check is pending, and if getInlineSpellChecker throws, then it's not
    // pending.
  }
  let waitingForEnded = isc && isc.spellCheckPending;
  let count = 0;

  function observe(subj, topic, data) {
    if (subj != editor)
      return;
    count = 0;
    let expectedTopic = waitingForEnded ? SPELL_CHECK_ENDED_TOPIC :
                        SPELL_CHECK_STARTED_TOPIC;
    if (topic != expectedTopic)
      Cu.reportError("Expected " + expectedTopic + " but got " + topic + "!");
    waitingForEnded = !waitingForEnded;
  }

  let os = Cc["@mozilla.org/observer-service;1"].
           getService(Ci.nsIObserverService);
  os.addObserver(observe, SPELL_CHECK_STARTED_TOPIC, false);
  os.addObserver(observe, SPELL_CHECK_ENDED_TOPIC, false);

  let timer = Cc["@mozilla.org/timer;1"].createInstance(Ci.nsITimer);
  timer.init(function tick() {
    // Wait an arbitrarily large number -- 50 -- turns of the event loop before
    // declaring that no spell checks will start.
    if (waitingForEnded || ++count < 50)
      return;
    timer.cancel();
    os.removeObserver(observe, SPELL_CHECK_STARTED_TOPIC);
    os.removeObserver(observe, SPELL_CHECK_ENDED_TOPIC);
    callback();
  }, 0, Ci.nsITimer.TYPE_REPEATING_SLACK);
};